A method for controlling temperature of ceramic sintering furnace

Abstract

The invention discloses a method for controlling the temperature of a ceramic sintering furnace, relates to the technical field of ceramic making, and solves the technical problem that in the prior art, ceramic embryos are usually placed in multiple layers, rows and columns in a ceramic embryo sintering furnace, and multiple ceramic embryos are heated unevenly in the same sintering furnace; the invention divides the sintering furnace into areas, calculates the placement spacing of the ceramic embryos in the sintering furnace, and places the ceramic embryos to be fired in the sintering furnace according to the placement spacing; sets a pre-sintering temperature, and preheats the temperature in the sintering furnace according to the pre-sintering temperature; sets a sintering temperature, determines the pressure strength inside the sintering furnace according to the sintering temperature, and completes the sintering of the ceramic embryos by pressure; cools the ceramic embryos after sintering according to a cooling strategy, and completes the temperature control of the ceramic embryo sintering furnace; the invention determines that the spacings between the ceramic embryos are different, so that each ceramic embryo can be heated evenly.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramics making, relates to a temperature regulation control technology, and specifically is a method for controlling the temperature of a ceramic embryo sintering furnace. Background Art

[0002] During the sintering process of ceramic embryos, temperature is a key factor affecting the sintering quality. Through precise temperature control, it is possible to ensure that the ceramic embryo material reaches an ideal sintering state during the sintering process, thereby obtaining high-quality ceramic embryo products; through the temperature control method, the sintering temperature can be monitored and precisely adjusted in real time, thereby meeting the temperature requirements of the ceramic embryo material during the sintering process; during the sintering process of ceramic embryos, the temperature control method can improve production efficiency; by optimizing the heating rate, the sintering time can be shortened while ensuring the sintering quality. In addition, precise temperature control can also reduce the sintering failure rate caused by temperature fluctuations and further improve production efficiency; constructing a temperature control method for ceramic embryo sintering furnaces can also help save energy and reduce consumption. Precise temperature control can reduce unnecessary energy waste and reduce production costs.

[0003] In the prior art ceramic embryo sintering furnace, ceramic embryos are usually placed in multiple layers, rows and columns. Multiple ceramic embryos may be heated unevenly in the same sintering furnace, resulting in excessive oxidation of the surface of some ceramic embryos, abnormal color changes, and even cracks and deformation, which seriously affects the appearance quality and mechanical properties of ceramic embryo products. At the same time, some ceramic embryos may not be burned dry inside, which may cause cracks on the ceramic embryo glaze and uneven color, resulting in unnecessary waste of resources.

[0004] The present invention provides a method for controlling the temperature of a ceramic embryo sintering furnace to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a method for controlling the temperature of a ceramic sintering furnace, which is used to solve the technical problem that multiple layers, rows and columns of ceramic embryos are usually placed in the ceramic embryo sintering furnace of the prior art, and multiple ceramic embryos will be heated unevenly in the same sintering furnace.

[0006] To achieve the above object, the first aspect of the present invention provides a method for controlling the temperature of a ceramic sintering furnace, comprising:

[0007] Based on the total volume of the accommodation space in the sintering furnace and the volume occupied by each ceramic embryo, the total volume of the accommodation space is divided into an even number of symmetrically distributed cubic areas;

[0008] Based on the preset number of rows, columns, and layers of the ceramic embryos in the cubic area and the distance between the ceramic embryos and the nearest heating surface, the placement spacing of the ceramic embryos in the sintering furnace is determined, and the ceramics to be fired are arranged in the sintering furnace according to the placement spacing;

[0009] Determine the heating rate of the temperature in the sintering furnace based on the room temperature, the preset sintering temperature, the first heating time, and the second heating time; wherein the first heating time is the time from room temperature to half of the difference between the pre-sintering temperature and room temperature, and the second heating time is the time from half of the difference between the pre-sintering temperature and room temperature to the pre-sintering temperature;

[0010] Determine the sintering pressure value of the pressurized interior of the sintering furnace based on the sintering temperature, the pre-sintering temperature, and the volume of the gas in the sintering furnace;

[0011] Maintaining the pre-sintering temperature and the sintering pressure value for a predetermined sintering time to complete the sintering of each ceramic embryo;

[0012] The ceramic embryo is cooled after sintering according to the cooling strategy to complete the temperature control of the ceramic embryo sintering furnace.

[0013] Preferably, based on the total volume of the accommodating space in the sintering furnace and the volume occupied by each ceramic embryo, the total volume of the accommodating space is divided into an even number of symmetrically distributed cubic areas, including:

[0014] Obtaining the total volume of the accommodation space in the sintering furnace that can accommodate ceramic embryos and the volume occupied by each ceramic embryo, wherein heaters are installed on all six sides of the total accommodation space in the sintering furnace;

[0015] The total accommodation space volume is gridded with the volume occupied by each ceramic embryo as a unit volume;

[0016] Taking any vertex where three surfaces intersect in the sintering furnace as the origin, the total accommodating space volume is divided into symmetrically distributed even-numbered cubic areas, wherein each of the cubic areas is connected to the origin, and the value range of the even number is greater than or equal to 4.

[0017] The present invention divides the sintering furnace into areas, takes any three-sided intersection corner in the sintering furnace as the origin, and constructs a 1 / 8 cubic area of ​​the total volume space connected to the origin, which facilitates regional management of the space in the furnace and greatly simplifies subsequent calculations.

[0018] Preferably, the method of determining the placement spacing of the ceramic embryos in the sintering furnace based on the preset number of rows, the preset number of columns, the preset number of layers of the ceramic embryos in the cubic area and the distance between the ceramic embryos and the nearest heating surface includes:

[0019] Based on the first uniformity coefficient, the preset number of rows of ceramic embryos in the cubic area, and the distance between the first row of ceramic embryos and the nearest heating surface, the placement spacing between the rows is determined by a row spacing calculation formula;

[0020] Based on the first uniformity coefficient, the preset number of rows of ceramic embryos in the cubic area, and the distance between the first row of ceramic embryos and the nearest heating surface, the placement spacing between the rows is determined by a row spacing calculation formula;

[0021] Based on the second uniformity coefficient, the preset number of layers of ceramic embryos in the cubic area, and the distance between the first layer of ceramic embryos and the nearest heating surface, the placement spacing between the layers is determined by a layer spacing calculation formula.

[0022] Preferably, the row spacing calculation formula is: ;

[0023] The column spacing calculation formula is: ;

[0024] The interlayer spacing calculation formula is: ;

[0025] in, is the spacing between the ceramic embryos in the i-th row and the ceramic embryos in the i-1th row, is the distance between the first row of ceramic embryos and the nearest heating surface, is the placement distance between the ceramic embryos in the i-1th row and the ceramic embryos in the previous row, i represents the number of rows; i=2, 3, 4, ..., n, and n is a positive integer;

[0026] is the placement distance between the ceramic embryos in the jth row and the ceramic embryos in the j-1th row, is the distance between the first row of ceramic embryos and the nearest heating surface, is the placement distance between the ceramic embryos in the j-1th row and the ceramic embryos in the previous row, j represents the number of rows; j=2, 3, 4, ..., n, and n is a positive integer;

[0027] is the placement distance between the k-th layer of ceramic embryos and the k-1-th row of ceramic embryos, is the distance between the first layer of ceramic embryo and the nearest heating surface (k=2), is the placement distance between the k-1th layer of ceramic embryos and the previous layer of ceramic embryos (k≧3); k=2, 3, 4, ..., n, and n is a positive integer;

[0028] α is the first uniformity coefficient, and β is the second uniformity coefficient.

[0029] The present invention calculates the spacing between rows, columns, and layers within a space of 1 / 8 of the total volume of the ceramic embryo, and places the ceramic embryos closer to the heating surface and farther away from the heating surface. By determining the specific scattered positions of the ceramic embryos, the space utilization is optimized while the ceramic embryos are heated evenly to the maximum extent, thereby avoiding cracking of the ceramic embryos due to thermal stress.

[0030] Preferably, the step of determining the first uniformity coefficient and the second uniformity coefficient comprises:

[0031] The first uniformity coefficient is determined by a first uniformity coefficient calculation formula based on the first adjustment coefficient, the second adjustment coefficient, the third adjustment coefficient, the fourth adjustment coefficient, the fifth adjustment coefficient, the directly heated area of ​​any ceramic embryo, the back heated area of ​​any ceramic embryo, the ceramic wall thickness of any ceramic embryo, the length of the widest diameter of any ceramic embryo, and the straight-line distance between the ceramic embryo and the nearest heater;

[0032] The second uniformity coefficient is determined by the second uniformity coefficient calculation formula based on the first adjustment coefficient, the second adjustment coefficient, the third adjustment coefficient, the fourth adjustment coefficient, the fifth adjustment coefficient, the sixth adjustment coefficient, the direct heating area of ​​any ceramic embryo, the back heating area of ​​any ceramic embryo, the ceramic wall thickness of any ceramic embryo, the length of the widest diameter of any ceramic embryo, the straight-line distance between the ceramic embryo and the nearest heater, and the specific heat capacity of the partition between each layer.

[0033] It should be noted that the adjustment coefficient is set according to the actual working conditions of the staff.

[0034] Preferably, the first uniformity coefficient calculation formula is: ;

[0035] The second uniformity coefficient calculation formula is: ;

[0036] Among them, q1 is the first adjustment coefficient; q2 is the second adjustment coefficient; q3 is the third adjustment coefficient; q4 is the fourth adjustment coefficient; q5 is the fifth adjustment coefficient; q6 is the sixth adjustment coefficient;

[0037] S1 is the directly heated area of ​​any ceramic embryo; S2 is the back heated area of ​​any ceramic embryo;

[0038] H1 is the thickness of the ceramic wall of any ceramic embryo; H2 is the length of the widest diameter of any ceramic embryo;

[0039] D1 is the straight-line distance between the ceramic embryo and the nearest heater; Q is the specific heat capacity of the partition between each layer.

[0040] It should be noted that the specific value of R depends on the type and unit system of the pressurized gas.

[0041] The present invention determines the uniformity coefficient so that the ceramic embryos farther away from the heating source have a longer interval, and the heating conditions of the ceramic embryos during the sintering process can be controlled more accurately. This helps to ensure that the ceramic embryos are evenly heated in all directions, thereby improving the sintering quality and making the ceramic embryos in the entire sintering furnace heated more comprehensively.

[0042] Preferably, the step of determining the heating rate of the temperature in the sintering furnace based on the room temperature, the preset sintering temperature, the first heating time, and the second heating time includes:

[0043] The ceramic blank is placed in a sintering furnace and the sintering furnace is evacuated to a vacuum state so that the internal space of the sintering furnace is in a low pressure state;

[0044] Determining the initial heating rate of the temperature in the sintering furnace by an initial heating rate calculation formula based on the room temperature, the pre-sintering temperature, the preset heating time from the room temperature to the pre-sintering temperature, and the first heating time;

[0045] The post-heating rate of the temperature in the sintering furnace is determined by a post-heating rate calculation formula based on the room temperature, the pre-sintering temperature, the preset heating time from the room temperature to the pre-sintering temperature, and the second heating time.

[0046] It should be noted that the cooling rate is set by the staff based on the material of the ceramic embryo, the real-time temperature and actual working experience; in actual application, the value of C2 is flexibly adjusted and optimized according to the specific situation.

[0047] The present invention controls the cooling rate to avoid cracking or deformation of the ceramic embryo material due to rapid temperature changes; ensures that the ceramic embryo material will not crack or deform due to thermal stress during the cooling process through two cooling stages; and avoids excessively fast cooling that may cause an increase in internal stress of the material by controlling the cooling rate within a set cooling rate.

[0048] Preferably, the initial heating rate calculation formula is: Q1=|C1-C0| / T1;

[0049] The calculation formula for the late heating rate is: Q2=|C-C1| / T2;

[0050] Wherein, Q1 is the initial heating rate; C is the pre-sintering temperature; C0 is the room temperature;

[0051] C1 is half of the difference between the pre-sintering temperature and the room temperature;

[0052] T1 is the first heating time, which is set equal to the preset heating time T, that is, T1=T;

[0053] Q2 is the later heating rate; T2 is the second heating time, which is set equal to 2 times the preset heating time T, that is, T2=2T.

[0054] The present invention uses a sintering furnace vacuum system to evacuate the furnace to remove gas and impurities in the furnace; after reaching T1, T1 is set equal to T, T2 is set equal to 2T, thereby reducing the heating rate of the temperature rise, making the ceramic embryo heated more evenly, reducing the thermal stress inside the ceramic embryo material and preventing cracking, and the pre-sintering process causes the ceramic embryo body to shrink and solidify to a certain extent, thereby improving its strength and reducing the shrinkage rate in the subsequent sintering process.

[0055] Preferably, the step of determining the sintering pressure value of the pressurized interior of the sintering furnace based on the sintering temperature, the pre-sintering temperature, and the volume of the gas in the sintering furnace comprises:

[0056] Based on the sintering temperature, the amount of the gas in the sintering furnace, the difference between the sintering temperature and the pre-sintering temperature, the volume of the gas in the sintering furnace, the compressibility coefficient of the gas in the sintering furnace and the sintering constant, the sintering pressure value of the pressurized interior of the sintering furnace is determined by a sintering pressure calculation formula;

[0057] Wherein, the sintering pressure calculation formula is P=(N×R×t / V)×θ;

[0058] P is the sintering pressure value of the pressurized sintering furnace; N is the amount of the substance in the gas in the sintering furnace; R is the sintering constant; t is the difference between the sintering temperature and the pre-sintering temperature; V is the volume of the gas in the sintering furnace; θ is the compression coefficient of the gas in the sintering furnace, and the compression coefficient represents the characteristic that the volume of the gas decreases when it is subjected to pressure;

[0059] Determining the compression factor includes:

[0060] Determining the compression coefficient by a compression coefficient calculation formula based on the predicted pressure value after the furnace is pressurized, the molar volume of the gas in the furnace, the sintering constant, and the predicted absolute temperature of the gas in the furnace after heating;

[0061] The compression coefficient calculation formula is: θ=(P1×M) / (R×t1);

[0062] θ is the compression coefficient; P1 is the predicted pressure value after the furnace is pressurized; M is the molar volume of the gas in the furnace; R is the sintering constant; t1 is the predicted absolute temperature of the gas in the furnace after heating.

[0063] The present invention applies pressure to the ceramic embryo under the action of high temperature and high pressure, so that the gaps inside the ceramic embryo are gradually filled, so that a dense solid ceramic embryo material is formed; when the volume and the amount of substance remain unchanged, the pressure is proportional to the temperature; when the temperature rises, the pressure will also increase accordingly.

[0064] Preferably, cooling the ceramic embryo after sintering according to the cooling strategy includes:

[0065] After sintering, turn off the heater and let the temperature in the furnace drop naturally within the set time; the set time is 2T, where T is the preset heating time;

[0066] After the set time, the cooling device is turned on, the cooling rate is controlled within the set cooling rate, and the temperature is accelerated by the cooling device until the temperature in the sintering furnace reaches the preset cooling temperature;

[0067] After the temperature in the sintering furnace reaches the preset cooling temperature, all cooling equipment is turned off to allow the temperature in the furnace to naturally drop to the room temperature.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] 1. The present invention ensures that each ceramic embryo is heated evenly by placing ceramic embryos at different gaps. The temperature sensor can monitor the temperature in the sintering furnace in real time to ensure that the ceramic embryo is always within a precise temperature range during preheating, sintering and cooling. Accurate temperature control helps to fuse ceramic embryo particles and optimize the crystal structure, thereby improving the performance of the sintered ceramic embryo. The pressure sensor can measure the pressure in the sintering furnace to ensure that appropriate pressure is applied during the sintering process, which helps to densify the ceramic embryo and improve its performance. By accurately controlling the pressure, sintering quality problems caused by insufficient or excessive pressure can be avoided.

[0070] 2. The present invention can optimize energy consumption and reduce unnecessary energy waste by precisely controlling the temperature and pressure in the sintering furnace. Efficient energy management helps to reduce production costs, thereby improving economic benefits. The present invention is adaptable to ceramic embryo materials of different types and specifications to meet diverse production needs. The integration of sensors and intelligent control systems makes the sintering process easy to adjust and optimize. Production personnel can flexibly adjust sintering parameters according to actual needs to achieve the best production effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0072] Figure 1 It is a specific schematic diagram of the temperature control process of the present invention;

[0073] Figure 2 The figure is a schematic diagram of the calculation process of the spacing between ceramic embryos of the present invention;

[0074] Figure 3 This is a schematic diagram of the specific steps of heating and sintering the ceramic embryo of the present invention;

[0075] Figure 4 It is a schematic diagram of the specific steps of cooling and sintering the ceramic embryo of the present invention. DETAILED DESCRIPTION

[0076] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0077] like Figure 1 As shown, the first aspect of the present invention provides a method for controlling the temperature of a ceramic sintering furnace, comprising:

[0078] Divide the sintering furnace into areas, calculate the placement spacing of the ceramic embryos in the sintering furnace, and place the ceramic embryos to be fired in the sintering furnace according to the placement spacing;

[0079] Set the pre-sintering temperature and preheat the temperature in the sintering furnace according to the pre-sintering temperature;

[0080] Set the sintering temperature, determine the pressure strength inside the sintering furnace according to the sintering temperature, and complete the sintering of the ceramic embryo by pressure;

[0081] The ceramic embryo is cooled after sintering according to the cooling strategy to complete the temperature control of the ceramic embryo sintering furnace.

[0082] In one embodiment, Figure 2As shown in the figure, the calculation process of the spacing between ceramic embryos is to obtain the total volume space in which ceramic embryos can be placed in the furnace, and the total volume space is gridded based on the volume occupied by each ceramic embryo; the same heater is installed on all six sides of the sintering furnace; any three-sided intersection corner in the sintering furnace is taken as the origin, and 1 / 8 of the total volume space connected to the origin is constructed into a cubic area;

[0083] The directly heated area of ​​the ceramic embryo is marked as S1, the back heated area is marked as S2, the ceramic wall thickness of the ceramic embryo is marked as H1, the length of the widest diameter of the ceramic embryo is marked as H2, the straight-line distance between different ceramic embryos and the nearest heater is marked as D1, and the specific heat capacity of the partition between each layer is marked as Q;

[0084] By calculation The first uniformity coefficient α is calculated;

[0085] By calculation The second uniformity coefficient β is calculated; wherein q1, q2, q3, q4, q5, q6 are adjustment coefficients for removing dimensions;

[0086] By calculation Calculate the width distance between the i-th row and the i-1-th row; where i represents the number of rows; i=2, 3, 4, ..., n, and n is a positive integer;

[0087] By calculation Calculate the length distance between the jth column and the j-1th column; where j represents the number of columns; j=2, 3, 4, ..., n, and n is a positive integer;

[0088] By calculation The height distance between the kth layer and the k-1th layer is calculated; k represents the number of layers; k=2, 3, 4, ..., n, and n is a positive integer; α and β are uniformity coefficients.

[0089] Embodiment 1: There is a ceramic sintering furnace that needs to adjust the sintering temperature. The total volume space in which ceramic embryos can be placed in the furnace is obtained, and the total volume space is gridded based on the volume occupied by each ceramic embryo; the same heater is installed on all six sides of the sintering furnace; any three-sided intersection corner in the sintering furnace is taken as the origin, and 1 / 8 of the total volume space connected to the origin is constructed to form a cubic area;

[0090] The direct heating area S1 of the ceramic blank in the first row is 3 , the back heating area S2 is 3.2 ; Mark the ceramic wall thickness H1 of the ceramic embryo as 2cm, the length H2 of the widest diameter of the ceramic embryo as 8cm, the straight-line distance D1 between different ceramic embryos and the nearest heater as 6cm, and the specific heat capacity Q of the partition between each layer as 1.72kJ / (kg·K); q1=q5=1 / , q2=q3=1 / cm, q4=1×(kg·K) / kJ,

[0091] By calculation The first uniformity coefficient α is calculated to be 0.49;

[0092] By calculation The second uniformity coefficient β is calculated to be 0.56;

[0093] Now, three layers of ceramic embryos need to be placed in the sintering furnace, with five rows and five columns of ceramic embryos placed on each layer;

[0094] By calculation The width distance between the i-th row and the i-1-th row is calculated; if X1=3cm, then X2=3.49cm, X3=4.47cm, X4=5.94cm, and X5=7.9cm; where X1 is the distance between the first row of ceramic embryos and the nearest heating surface;

[0095] By calculation Calculate the length between the jth column and the j-1th column; set Y1=3cm, then Y2=3.49cm, Y3=4.47cm, Y4=5.94cm, Y5=7.9cm; where, is the distance between the first row of ceramic embryos and the nearest heating surface;

[0096] By calculation The height distance between the kth layer and the k-1th layer is calculated; if Z1=4cm, then Z2=4.56cm, Z3=5.68cm, where X1 is the distance between the first layer of ceramic embryo and the nearest heating surface.

[0097] It should be noted that no ceramic embryos are placed at the four corner vertices of the first layer and the last layer of the sintering furnace, that is, no ceramic embryos are placed at the eight vertices of the cube-shaped sintering furnace, so as to ensure that the ceramics on each side can receive the same heating effect; the specific spacing of each row, each column, and each layer is obtained by calculating the cube area, and another symmetrical cube area with the same volume as the current cube area is obtained by taking the bottom surface of the cube area (or the top surface of the cube area) as the symmetry plane, and the ceramic embryo positions of the cube area are symmetrically placed with the ceramic embryo positions of the symmetrical cube area; since the volume of the cube area and the volume of the symmetrical cube area are both 1 / 8 of the total volume space, the volume of the cube area and the volume of the symmetrical cube area are added together to obtain one quarter of the total volume space of the ceramic embryo;

[0098] Taking any side of a quarter of the total volume of the ceramic embryo away from the heating surface as a symmetry plane, a symmetrical quarter of the total volume of the ceramic embryo is obtained; placing the ceramic embryo position on the side of the quarter of the total volume of the ceramic embryo symmetrically to the symmetrical quarter of the total volume of the ceramic embryo; adding the quarter of the total volume of the ceramic embryo to the symmetrical quarter of the total volume of the ceramic embryo to obtain a half of the total volume of the ceramic embryo;

[0099] A symmetrical half ceramic embryo total volume space is obtained by taking the side of the half ceramic embryo total volume space away from the heating surface as the symmetry plane; and the ceramic embryo position on the side of the half ceramic embryo total volume space is placed symmetrically to the symmetrical half ceramic embryo total volume space.

[0100] like Figure 3 As shown, the specific steps of heating and sintering the ceramic embryo are to load the ceramic embryo into a furnace and evacuate the furnace to make it under low pressure;

[0101] The time from room temperature to the pre-sintering temperature through the heater in an empty furnace without adding a ceramic embryo is obtained from the database and marked as T; wherein the pre-sintering temperature is marked as C;

[0102] When the ceramic embryo is added, the room temperature is marked as C0, and half of the difference between the pre-sintering temperature and the room temperature is marked as C1; the time from the room temperature to half of the difference between the pre-sintering temperature and the room temperature is marked as T1, and the time from half of the difference between the pre-sintering temperature and the room temperature to the pre-sintering temperature is marked as T2;

[0103] Set T1=T, and calculate the initial heating rate from room temperature to half the difference between the pre-sintering temperature and room temperature by the calculation formula Q1=|C1-C0| / T1;

[0104] Set T2=2T, and calculate the post-heating rate from half the difference between the pre-sintering temperature and room temperature to the pre-sintering temperature by the calculation formula Q2=|C1-C0| / T2;

[0105] The temperature in the furnace is raised to the pre-sintering temperature by a heater by setting a heating rate; wherein the set heating rate includes: an initial heating rate and a later heating rate;

[0106] When the pre-sintering temperature is reached, the pressurization system is turned on, and the volume of the gas in the furnace is marked as V, the difference between the sintering temperature and the pre-sintering temperature is recorded as t, and the amount of gas in the furnace is marked as N;

[0107] The specific pressure value of the pressurization is calculated by the formula P=(NRt / V)×θ; where R is a constant, and the compression coefficient of the gas in the furnace is marked as θ, which is used to characterize the characteristics of the volume reduction of the gas when it is subjected to pressure;

[0108] The compression coefficient of the gas in the furnace is calculated by the formula θ= (P1×M) / (R×t1); where M is the molar volume of the gas in the furnace, t1 is the absolute temperature of the gas in the furnace, and P1 is the actual pressure value in the furnace.

[0109] Example 2: Load the ceramic embryo into a furnace and evacuate the furnace to a vacuum state so that the furnace is in a low pressure state;

[0110] The time from room temperature to the pre-sintering temperature through the heater in an empty furnace without adding a ceramic embryo is obtained from the database and marked as 15 minutes; wherein the pre-sintering temperature is marked as 230°C;

[0111] When the ceramic embryo is added, the room temperature C0 is marked as 30°C, and the half of the difference between the pre-sintering temperature and the room temperature C1 is 130°C; the time T1 from the room temperature to half of the difference between the pre-sintering temperature and the room temperature is marked as 15 minutes, and the time T2 from half of the difference between the pre-sintering temperature and the room temperature to the pre-sintering temperature is 30 minutes;

[0112] The initial heating rate from room temperature to half the difference between the pre-sintering temperature and room temperature is calculated by the formula Q1=|C1-C0| / T1 to be Q1=|130-30| / 15=6.67℃ / min;

[0113] The calculation formula Q2=|C1-C0| / T2 is used to calculate the post-heating rate Q2=|230-130| / 30=3.33℃ / min from half the difference between the pre-sintering temperature and the room temperature to the pre-sintering temperature;

[0114] The temperature in the furnace is raised to the pre-sintering temperature of 230°C by setting the heating rate through the heater;

[0115] The calculation formula θ=(P1×M) / (R×t1)is used to calculate the gas compression coefficient θ=(6864×22.4) / (287.05×503.15)=1.065; where the constant R is 287.05J / (kg\cdotpK), the molar volume M of the gas in the furnace is 22.4L / mol, t1 is the absolute temperature of the gas in the furnace, and the actual pressure value P1 in the furnace is 1.84atm;

[0116] Turn on the pressurization system, mark the volume of the gas in the furnace as V = 22.6L / mol, the difference between the sintering temperature and the pre-sintering temperature as t = 120°C, and the amount of gas in the furnace as N = 28.98mol;

[0117] Through the calculation formula P = (NRt / V) × θ = (28.98 × 287.05 × 350 / 22.6) × 1.065 = 47074Pa, that is, adding 47074Pa to the actual pressure P1 in the furnace can make up for the temperature difference of 120℃.

[0118] In one embodiment, Figure 4 As shown in the figure, the specific steps of cooling and sintering the ceramic embryo are as follows: after sintering, the heater is turned off to allow the temperature in the furnace to drop naturally within the set time; wherein the set time is 2T;

[0119] After the set time, the cooling device is turned on, the cooling rate is controlled within the set cooling rate, and the temperature is accelerated by the cooling device until the temperature in the sintering furnace reaches C2;

[0120] When the temperature in the sintering furnace reaches C2, turn off all cooling equipment and let the temperature in the furnace drop naturally to C0.

[0121] It should be noted that the cooling rate is set by the staff based on the material of the ceramic embryo, the real-time temperature and actual working experience; in actual application, the value of C2 is flexibly adjusted and optimized according to the specific situation.

[0122] Example 3: After sintering, the heater is turned off. At this time, the temperature in the furnace is 230°C. The temperature in the furnace is allowed to drop naturally within 30 minutes. At this time, the monitored temperature in the furnace is 180°C.

[0123] According to the staff's actual work experience and the material of this batch of ceramic embryos, cracks are prone to occur when the cooling rate exceeds 10℃ / min after 180℃. After natural cooling at a temperature of 130℃, this batch of ceramics no longer cracks;

[0124] After 30 minutes, the cooling device is turned on, the cooling rate is controlled within 10°C / min, and the temperature is accelerated by the cooling device until the temperature in the sintering furnace reaches 130°C;

[0125] (180℃-130℃) / 10℃ / min=5min, so the cooling equipment should last for more than 5 minutes after reaching a fixed cooling rate.

[0126] Part of the data in the above calculation formula is calculated by removing the dimension and taking its numerical value. The calculation formula is a calculation formula that is closest to the actual situation obtained by software simulation of a large amount of collected data; the preset parameters and preset thresholds in the calculation formula are set by technical personnel in this field according to actual conditions or obtained through simulation of a large amount of data.

[0127] The working principle of the present invention is as follows: the present invention divides the sintering furnace into areas, calculates the placement spacing of each row, column and layer of ceramic embryos in the sintering furnace, and places the ceramic embryos to be fired in the sintering furnace according to the placement spacing; sets the pre-sintering temperature, and preheats the temperature in the sintering furnace according to the pre-sintering temperature; sets the sintering temperature, determines the pressurization strength inside the sintering furnace according to the sintering temperature, and completes the sintering of the ceramic embryos by pressurization; cools the ceramic embryos after sintering according to the cooling strategy, and completes the temperature control of the ceramic embryo sintering furnace.

[0128] Part of the data in the above formula is calculated by removing the dimension and taking its numerical value. The formula is a formula closest to the actual situation obtained by software simulation of a large amount of collected data; the preset parameters and preset thresholds in the formula are set by technical personnel in this field according to actual conditions or obtained through simulation of a large amount of data.

[0129] The working principle of the present invention is as follows: the sintering furnace is divided into areas, the placement spacing of each row, column and layer of ceramic embryos in the sintering furnace is calculated, and the ceramic embryos to be fired are placed in the sintering furnace according to the placement spacing; the pre-sintering temperature is set, and the temperature in the sintering furnace is preheated according to the pre-sintering temperature; the sintering temperature is set, and the pressure strength inside the sintering furnace is determined according to the sintering temperature, and the sintering of the ceramic embryos is completed by pressurization; the ceramic embryos after sintering are cooled according to the cooling strategy, and the temperature control of the ceramic embryo sintering furnace is completed.

[0130] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A method for controlling the temperature of a ceramic sintering furnace, characterized in that: include: Based on the total volume of the accommodation space in the sintering furnace and the volume occupied by each ceramic embryo, the total volume of the accommodation space is divided into an even number of symmetrically distributed cubic areas; Based on the preset number of rows, columns, and layers of the ceramic embryos in the cubic area and the distance between the ceramic embryos and the nearest heating surface, the placement spacing of the ceramic embryos in the sintering furnace is determined, and the ceramics to be fired are arranged in the sintering furnace according to the placement spacing; Determine the heating rate of the temperature in the sintering furnace based on the room temperature, the preset sintering temperature, the first heating time, and the second heating time; wherein the first heating time is the time from room temperature to half of the difference between the pre-sintering temperature and room temperature, and the second heating time is the time from half of the difference between the pre-sintering temperature and room temperature to the pre-sintering temperature; Determine the sintering pressure value of the pressurized interior of the sintering furnace based on the sintering temperature, the pre-sintering temperature, and the volume of the gas in the sintering furnace; Maintaining the pre-sintering temperature and the sintering pressure value for a predetermined sintering time to complete the sintering of each ceramic embryo; The temperature of the ceramic embryo after sintering is reduced according to the cooling strategy to complete the temperature control of the ceramic embryo sintering furnace; Based on the first uniformity coefficient, the preset number of rows of ceramic embryos in the cubic area, and the distance between the first row of ceramic embryos and the nearest heating surface, the placement spacing between the rows is determined by a row spacing calculation formula; Based on the first uniformity coefficient, the preset number of rows of ceramic embryos in the cubic area, and the distance between the first row of ceramic embryos and the nearest heating surface, the placement spacing between the rows is determined by a row spacing calculation formula; Based on the second uniformity coefficient, the preset number of layers of ceramic embryos in the cubic area, and the distance between the first layer of ceramic embryos and the nearest heating surface, the placement spacing between the layers is determined by a layer spacing calculation formula; The row spacing calculation formula is: ; The column spacing calculation formula is: ; The interlayer spacing calculation formula is: ; in, is the spacing between the ceramic embryos in the i-th row and the ceramic embryos in the i-1th row, is the distance between the first row of ceramic embryos and the nearest heating surface, is the placement distance between the ceramic embryos in the i-1th row and the ceramic embryos in the previous row, i represents the number of rows; i=2, 3, 4, ..., n, and n is a positive integer; is the placement distance between the ceramic embryos in the jth row and the ceramic embryos in the j-1th row, is the distance between the first row of ceramic embryos and the nearest heating surface, is the placement distance between the ceramic embryos in the j-1th row and the ceramic embryos in the previous row, j represents the number of rows; j=2, 3, 4, ..., n, and n is a positive integer; is the placement distance between the k-th layer of ceramic embryos and the k-1-th row of ceramic embryos, is the distance between the first layer of ceramic embryo and the nearest heating surface, is the placement distance between the k-1th layer of ceramic embryos and the previous layer of ceramic embryos, k represents the number of layers; k=2, 3, 4, ..., n, and n is a positive integer; α is the first uniformity coefficient, and β is the second uniformity coefficient.

2. The method for controlling the temperature of a ceramic sintering furnace according to claim 1, characterized in that: Based on the total volume of the accommodating space in the sintering furnace and the volume occupied by each ceramic embryo, the total volume of the accommodating space is divided into an even number of symmetrically distributed cubic areas, including: Obtaining the total volume of the accommodation space in the sintering furnace that can accommodate ceramic embryos and the volume occupied by each ceramic embryo, wherein heaters are installed on all six sides of the total accommodation space in the sintering furnace; The total accommodation space volume is gridded with the volume occupied by each ceramic embryo as a unit volume; Taking any vertex where three surfaces intersect in the sintering furnace as the origin, the total accommodating space volume is divided into symmetrically distributed even-numbered cubic areas, wherein each of the cubic areas is connected to the origin, and the value range of the even number is greater than or equal to 4.

3. The method for controlling the temperature of a ceramic sintering furnace according to claim 1, characterized in that: The step of determining the first uniformity coefficient and the second uniformity coefficient comprises: The first uniformity coefficient is determined by a first uniformity coefficient calculation formula based on the first adjustment coefficient, the second adjustment coefficient, the third adjustment coefficient, the fourth adjustment coefficient, the fifth adjustment coefficient, the directly heated area of ​​any ceramic embryo, the back heated area of ​​any ceramic embryo, the ceramic wall thickness of any ceramic embryo, the length of the widest diameter of any ceramic embryo, and the straight-line distance between the ceramic embryo and the nearest heater; The second uniformity coefficient is determined by the second uniformity coefficient calculation formula based on the first adjustment coefficient, the second adjustment coefficient, the third adjustment coefficient, the fourth adjustment coefficient, the fifth adjustment coefficient, the sixth adjustment coefficient, the direct heating area of ​​any ceramic embryo, the back heating area of ​​any ceramic embryo, the ceramic wall thickness of any ceramic embryo, the length of any ceramic embryo at the widest diameter, the straight-line distance between the ceramic embryo and the nearest heater, and the specific heat capacity of the partition between each layer.

4. The method for controlling the temperature of a ceramic sintering furnace according to claim 3, characterized in that: The first uniformity coefficient calculation formula is: ; The second uniformity coefficient calculation formula is: ; Among them, q1 is the first adjustment coefficient; q2 is the second adjustment coefficient; q3 is the third adjustment coefficient; q4 is the fourth adjustment coefficient; q5 is the fifth adjustment coefficient; q6 is the sixth adjustment coefficient; S1 is the directly heated area of ​​any ceramic embryo; S2 is the back heated area of ​​any ceramic embryo; H1 is the thickness of the ceramic wall of any ceramic embryo; H2 is the length of the widest diameter of any ceramic embryo; D1 is the straight-line distance between the ceramic embryo and the nearest heater; Q is the specific heat capacity of the partition between each layer.

5. The method for controlling the temperature of a ceramic sintering furnace according to claim 1, characterized in that: The step of determining the heating rate of the temperature in the sintering furnace based on the room temperature, the preset sintering temperature, the first heating time, and the second heating time includes: The ceramic blank is placed in a sintering furnace and the sintering furnace is evacuated to a vacuum state so that the internal space of the sintering furnace is in a low pressure state; Determining the initial heating rate of the temperature in the sintering furnace by an initial heating rate calculation formula based on the room temperature, the pre-sintering temperature, the preset heating time from the room temperature to the pre-sintering temperature, and the first heating time; The post-heating rate of the temperature in the sintering furnace is determined by a post-heating rate calculation formula based on the room temperature, the pre-sintering temperature, the preset heating time from the room temperature to the pre-sintering temperature, and the second heating time.

6. The method for controlling the temperature of a ceramic sintering furnace according to claim 5, characterized in that: The initial heating rate calculation formula is: Q1=|C1-C0| / T1; The calculation formula for the late heating rate is: Q2=|C-C1| / T2; Wherein, Q1 is the initial heating rate; C is the pre-sintering temperature; C0 is the room temperature; C1 is half of the difference between the pre-sintering temperature and the room temperature; T1 is the first heating time, which is set equal to the preset heating time T, that is, T1=T; Q2 is the later heating rate; T2 is the second heating time, which is set equal to 2 times the preset heating time T, that is, T2=2T.

7. The method for controlling the temperature of a ceramic sintering furnace according to claim 1, characterized in that: The method of determining the sintering pressure value of the pressurized interior of the sintering furnace based on the sintering temperature, the pre-sintering temperature, and the volume of the gas in the sintering furnace comprises: Based on the sintering temperature, the amount of the gas in the sintering furnace, the difference between the sintering temperature and the pre-sintering temperature, the volume of the gas in the sintering furnace, the compressibility coefficient of the gas in the sintering furnace and the sintering constant, the sintering pressure value of the pressurized interior of the sintering furnace is determined by a sintering pressure calculation formula; Wherein, the sintering pressure calculation formula is P=(N×R×t / V)×θ; P is the sintering pressure value of the pressurized sintering furnace; N is the amount of the substance in the gas in the sintering furnace; R is the sintering constant; t is the difference between the sintering temperature and the pre-sintering temperature; V is the volume of the gas in the sintering furnace; θ is the compression coefficient of the gas in the sintering furnace, and the compression coefficient represents the characteristic that the volume of the gas decreases when it is subjected to pressure; Determining the compression factor includes: Determining the compression coefficient by a compression coefficient calculation formula based on the predicted pressure value after the furnace is pressurized, the molar volume of the gas in the furnace, the sintering constant, and the predicted absolute temperature of the gas in the furnace after heating; The compression coefficient calculation formula is: θ=(P1×M) / (R×t1); θ is the compression coefficient; P1 is the predicted pressure value after the furnace is pressurized; M is the molar volume of the gas in the furnace; R is the sintering constant; t1 is the predicted absolute temperature of the gas in the furnace after heating.

8. The method for controlling the temperature of a ceramic sintering furnace according to claim 1, characterized in that: The step of cooling the ceramic embryo after sintering according to the cooling strategy includes: After sintering, turn off the heater and let the temperature in the furnace drop naturally within the set time; the set time is 2T, where T is the preset heating time; After the set time, the cooling device is turned on, the cooling rate is controlled within the set cooling rate, and the temperature is accelerated by the cooling device until the temperature in the sintering furnace reaches the preset cooling temperature; After the temperature in the sintering furnace reaches the preset cooling temperature, all cooling equipment is turned off to allow the temperature in the furnace to naturally drop to the room temperature.

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